Historical and recent evolution of the Reno river mouth and adjacent areas.

The Reno river mouth and the adjacent areas are characterized by sandy beaches, wide brackish lagoons and extended salt marshes. The study area belongs to the Po Delta Park of the Emilia Romagna Region. The study consists in a reconstruction of the coastal evolution from the beginning of the 19th century to the present. It is an analysis of the historical and geodetic cartography and of the photogrammetry. At the beginning of the XIX century the river mouth was oriented eastward but, after some human modifications to its terminal stretch, the river mouth showed a gradually northward shift, inducing the growth of a spit; in the last century the spit entered in an erosive phase, which caused the reduction and the thinning of its shape. At the same time the northward movement of the sediment coming from the Reno river caused the occlusion of the outlet of the Bellocchio Channel inducing a decrease of water exchange between the “Sacca di Bellocchio” and the Adriatic sea. From a naturalistic point of view, the “Sacca di Bellocchio” is one of the most important area of the Po Delta Park; the worrying forecasts for the next decades give uncertain expectation for this esteemed, sensitive ecosystem. The territorial setting suggests the possibility of increased intensification of flooding events, the amplifications of beach erosion, an instability in the water circulation and an enhanced intrusion of the saline wedge into the channels and into the coastal aquifers. Even in a short-term scale, all the above factors will be able to significantly modify this ecosystem.